Setting up read-only SNMP community and sending SNMP traps to a central SNMP trap receiver, on Cisco devices. Some options like Spanning-tree, under the trap configuration, will not neccessary be available on all devices.

Configuring the SNMP community string and allow only the “Trap server” to connect “read-only” mode to it:

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snmp-server community omsa_checker ro 70
access-list 70 permit <trap_server_ip> <trap_server_subnet>
snmp-server host <trap_server_ip> version 2c <some_comunity_string>

Specifying specific events that will trigger a message to be send to the “Trap server”:

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snmp-server enable traps envmon fan shutdown supply temperature status
snmp-server enable traps bridge newroot topologychange
snmp-server enable traps stpx inconsistency root-inconsistency loop-inconsistency
snmp-server enable traps vlan-membership
snmp-server enable traps errdisable
snmp-server host <trap_server_ip> version 2c <some_comunity_string> envmon bridge stpx vlan-membership errdisable

Verifying the SNMP configuration:

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switch#show snmp host

Having a “Trap server” with the above configuration, makes life much easier to monitor the network or be notified of events that will normally not be picked up with general monitoring software. I am specifically pointing here at Spanning-tree related events.